The present invention relates to puncturing sets such as are generally used in the healthcare field and in particular for the puncturing of pathological, liquid-filled body cavities.
Such puncturing sets are used to collect and remove undesirable liquid accumulations from body cavities or for extracting body fluid samples for diagnostic purposes. It is conventional to use hollow needles, such as cannulas or trocars, which pierce through the surrounding body wall to reach the body cavity that is to be evacuated. Following puncturing, the liquid is withdrawn through the hollow needle. It is a disadvantage of such known arrangements that the needle, which remains in the body cavity while the liquid is withdrawn, can injure the body tissue that surrounds the hollow space.
The use of so-called "Braunulen" for puncturing is also known. A Braunule is a piercing instrument which has a hollow needle disposed inside a cannula-like plastic tube. The pointed end of the needle extends beyond the forward end of the plastic tubing. A Braunule is conventionally introduced into the body, for example into a vein, by piercing the body wall with the hollow needle and by then pushing the plastic tubing as far as needed into the body. The needle is then pulled out of the plastic tubing and removed so that the plastic tubing remains in the body, for example in the vein, for connection to an infusion system, for example. The use of Braunulen for puncturing has the disadvantage that the portion of the plastic tubing that remains in the body cavity during the withdrawal of the body fluid can become pinched due to body movements, or moving body organs. When this is encountered, the further withdrawal of liquid can become difficult or impossible.
The above two discussed puncturing methods are particularly in use in connection with so-called "Pleuroergussen", i.e. liquid accumulations in the body cavity surrounding the lung. Here it is necessary to prevent the pointed needle end from injuring the lung as it moves during normal breathing and, over the longer term, assure a reliable removal of even large liquid accumulations.